Benzaldehyde Aldol Condensation Cross-coupling Reactions Dft Acid-base Sites Heterogeneous Catalysis

External authors:

• Cesar Pazo ( Pontificia Universidad Catolica de Chile , Millennium Nuclei Catalyt Proc Sustainable Chem )
• Esteban Camu ( Pontificia Universidad Catolica de Chile , Millennium Nuclei Catalyt Proc Sustainable Chem )
• Angel Leiva ( Pontificia Universidad Catolica de Chile )
• Yoan Hidalgo-Rosa ( Universidad Autonoma de Chile , Millennium Nuclei Catalyt Proc Sustainable Chem )
• Ximena Zarate ( Universidad Autonoma de Chile , Millennium Nuclei Catalyt Proc Sustainable Chem )
• Ana Belen Dongil ( CSIC - Instituto de Catalisis y Petroleoquimica (ICP) )
• E. Schott ( Pontificia Universidad Catolica de Chile , Millennium Nuclei Catalyt Proc Sustainable Chem )
• Ana Belen Dongil ( CSIC - Instituto de Catalisis y Petroleoquimica (ICP) )

Abstract:

Mono-and bimetallic UiO-66 nanocatalysts were synthesized using the solvothermal synthesis method and evaluated in the aldol condensation reaction of benzaldehyde and acetone in a batch reactor. N2 physisorption, thermogravimetric analysis, temperature-programmed desorption of ammonia, X-ray diffraction, field-emission scanning electron microscopy-energy-disper-sive X-ray, X-ray photoelectron spectroscopy, potentiometric titration, and Fourier transform infrared were used to characterize the nanocatalysts. The higher activity exhibited by the Zr/Hf-UiO66 catalyst could be attributed to the lower orbital energy interaction with benzaldehyde, as shown by density functional theory. A synergetic effect is observed for the bimetallic UiO-66 nanocatalyst between Zr and Hf, obtaining a higher reaction rate than the monometallic nanocatalysts. Meanwhile, this antagonistic effect was shown in the bimetallic catalysts between Zr and Ce, which was less active than the monometallic UiO-66 catalyst due to free COOH generated during the synthesis. Finally, the selectivity results showed that incorporating Hf and Ce on Zr-UiO-66 favors benzalacetone formation by cross-coupling condensation of benzaldehyde and acetone at isoconversion conditions.